For comparison purposes, can you try using the GMSK modulation? Justremove the '-m dqpsk' from the command line.

-Johnathan

Johnathan,

I tried gmsk and dbpsk once again, the results of PER are shown below:

for gmsk:

-r 400k -s 200 nearly 100% right

-r 400k -s 500 nearly 98% right

-r 400k -s 1500 nearly 97% right

for dbpsk: all of the cases gave almost 0% PER, which means communication were very good!

Johnathan, could you tell me the detailed configurations of your setup, for example, which demo files were you using, what were the arguments you used for your transmission? I also hope the data I got is useful for your development. Thank you!!!